Duff Brewry Bar

Ok, I may not understand the rules here. I admit that this is my first HHN event in Orlando.

So I go back to Springfield and check into the holding area and find a seat at the bar. Im going solo so if I get up while I’m in this crowd I’ll loose my seat. But that’s OK I’m sitting at the bar. I should be good.
A group of five or so get a couple refills while sitting across from me. I finally stop the bar tender and ask for a drink. He tells me that I have to get in line and can’t serve me while at the bar.
Ok. And these people just got another round from there seats and I have been told that if he serves me he will get in trouble.
Looks to me like some sort of buddy system or something.